Amino-functionalized carbon fiber/polyamide 6 composites with enhanced interfacial and mechanical properties

Polyamines with different amino numbers were introduced on the surface of carbon fiber (CF) by a chemical grafting method to improve the interfacial properties of CF/polyamide 6 (PA6) composites. First, a carboxyl group was introduced on the surface of CF, and then polyamine was grafted onto the pretreated CF. The chemical structure of CF was confirmed by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), polarized light microscopy, and Fourier transform infrared spectroscopy (FTIR), and the performance test results of the composites were systematically analyzed. The content of N on the surface of the modified CF reached 18.92%; the interfacial shear strength (IFSS) and tensile strength of the modified CF/PA6 composite reached 58.6 MPa, respectively, which were 41.5% and 45.5% higher than those of unmodified CF/PA6 composites. The above results confirm that amino-functionalized grafting modification is an effective method to improve the interfacial compatibility and adhesion of composites to improve the mechanical properties of composites.